But The Sun found stores selling them for the same price, ­hitting shoppers with a sneaky rise equivalent to 17 per cent.

Builder Simon Akroyd, 52, of Bedford, spotted the ploy when he gave workers their usual choccy perk and there weren’t enough to go round. He said: “They thought I was trying to dupe them, and weren’t happy.”

Makers have used the trick, called “shrinkflation”, on 2,500 grocery products in five years.

The Sun recently revealed that top Haribo favourites and Walnut Whips had got smaller.

McVitie’s admitted “adjusting” Jaffa Cake packs but said it also cut its recommended price.